The present invention relates to power supplies and, more particularly, to a laser power supply in which the laser tube and the power supply comprise a single structure.
In present day optical bar code scanners which are utilized in checkout counters for reading coded labels attached to the purchased merchandise items, a demand has arisen for the development of compact scanners which can be used where the checkout operator is in a sitting position during the checkout operation. An example of this type of optical scanner can be found in U.S. Pat. No. 4,797,551 which is assigned to the assignee of the present application. It was found that the power supply and the laser source were the principal elements that needed replacement during the operating life of the scanner and that such elements required the scanner to be removed from the counter to provide such replacement. This resulted in an interruption of the checkout operation which negatively affected the sales of the scanner. In order to construct a laser power supply that could be easily replaced in the field, the power supplies were constructed in modular form but it was found that the output power of the laser tube varied between modules thus producing uneven scanning results.